The advent of storage as a service offered by cloud providers and facilitating efficient analytics over storage as a service, has opened an entire new area of research over methods for secure data storage and efficient search and retrieval. Numerous works have been done over secure data storage and efficient search and retrieval, with Boneh et al's method for trapdoor generation and corresponding search pioneering in the area. Boneh's method was based on double hashing of the keyword for trapdoor generation. Park et al's scheme improvised the trapdoor generation by providing a generation mechanism comprising usage of a single hash function over the keyword. But all these schemes suffer from offline key word guessing attacks. The trapdoors are generated statically, i.e., the same trapdoor is generated every time for a particular key word, making it vulnerable to brute force attack over the limited range of dictionary words by a misfeasor, masquerader or clandestine user.
Work for architectural design framework was proposed in the cryptographic cloud storage scheme. In the existing schemes, to search for any keyword, the data user supplies the keyword to the data managing authority to get a corresponding trapdoor which is searched at the cloud database. Since keywords form a very limited range of dictionary words, the present schemes are liable to an offline keyword guessing attack, i.e. the user can sniff a trapdoor from the network and then by applying a brute force attack over it, they can guess the corresponding keyword.
The existing processes have limitations such as searchable encryption that uses the same trapdoor (unique static), for the same keyword to be searched for, i.e. there is a one to one mapping between the keyword and trapdoor. The existing methods are vulnerable to online and offline dictionary attacks. All existing schemes are based on single trapdoor search.
Thus, there is a need to overcome the problems of the existing technologies.